The area of the first circle would equal 9*pi (remember that area is pi*r^2 and r is half of diameter, which is 3 in this case).
The area of the second corcle would equal 144*pi (remember that area is pi*r^2 and r is half of diameter, which is 12 in this case).
Now compare the areas with a ratio and simplify
9*pi to 144* pi
1*pi to 16*pi
Final answer: C